Thermal connector for joining mobile electronic devices to docking stations

ABSTRACT

A heat exchanger. A first heat transfer element has an end which forms an engaging surface. A second heat transfer element has a receptacle portion which is integrally formed and has an engaging surface that is urged against the engaging surface of the first heat transfer element when the first heat transfer element and the second heat transfer element are mated.

BACKGROUND

[0001] 1. Field of the Disclosure

[0002] The present disclosure pertains to the field of heat removal fromelectronic components. More particularly, this disclosure relates toheat removal from a computing device which mates with another devicesuch as a docking station.

[0003] 2. Description of Related Art

[0004] Faster and more powerful computer components allow the design andconstruction of higher performance portable computing devices such aslaptop or notebook computers. Unfortunately, the use of such faster andmore powerful computer components often results in increased heatgeneration by such computing devices. Thus, improved heat dissipationtechnology is often needed to maintain operating temperatures ofportable computing devices within the same range as their predecessorsor some other acceptable range.

[0005] Maintaining operating temperatures of computer system componentsbelow certain levels is important to ensure performance, reliability,and safety. Most integrated circuits have specified maximum operatingtemperatures, above which the manufacturer does not recommend operation.Additionally, most integrated circuits have timing specifications thatspecify a window of time in which input signals need to be received forproper functioning as well as a window of time in which output signalsare generated under normal operating conditions. Transistors, thebuilding blocks of integrated circuits, tend to slow down as operatingtemperature increases. Thus, a computer system that operates itsintegrated circuits close to or beyond recommended timing specificationsmay fail as temperature increases.

[0006] Additionally, integrated circuits may be physically damaged iftemperatures elevate beyond those recommended. Such physical damageobviously can impact system reliability. Finally, the computer systemcasing should be kept at a temperature which is safe for human contact.This may necessitate spreading of heat throughout a computer system baseor efficiently expelling heat to avoid hot spots near certain componentssuch as a processor.

[0007] Typically, heat sinks, fans, and heat pipes are employed todissipate heat from integrated circuits and other electronic components.Increases in heat generation are often accommodated by simply increasingthe quantity or size of these heat dissipation elements. The relativelysmall size of a portable computing device, however, complicates heatdissipation by limiting airflow, crowding heat generating components,and reducing the space available for heat dissipation devices.

[0008] A docking station is a well known computing device that mateswith a portable computing device to allow the portable computing deviceaccess to various resources available to the docking station. Manyportable devices such as personal digital assistants and/or organizersand communication devices may utilize such a docking stationarrangement. Additionally, many portable computers (i.e., laptops ornotebook computers) can operate in a docking station arrangement.Alternatively, a docking station may be any device that mates with,receives, or holds a portable computing or other electronic device.

[0009] In the case of portable computers, the base of the portablecomputer typically connects to the docking station to allow use of alarger monitor and a fall size keyboard among other things. Thisadvantageously allows a portable computer user to operate a portablecomputing device in a more ergonomic desktop computer setting ratherthan using the small keyboard and screen often provided in a portablecomputing device.

[0010] Mating a portable computing device with a docking station oftencompounds the difficulty of cooling portable computing devices becausethe display is typically closed. This reduces the natural or passivecooling capability of the portable computing device because convectiveairflow over the top of the base is mostly blocked by the screen.Additionally, portable computers are now being designed to operate in ahigher power mode when docked at the docking station, resulting in thegeneration of more heat to dissipate.

[0011] The prior art does not sufficiently take advantage of dockingstations to dissipate heat. Particularly, the prior art does not providean economical heat exchanger which transfers heat from a portablecomputing device to a docking station for dissipation via connectorswhich are designed to withstand repeated insertion and removal cyclesand still provide low thermal resistance between the portable computingdevice and the docking station.

SUMMARY

[0012] A heat exchanger is disclosed. A first heat transfer element hasan end which forms an engaging surface. A second heat transfer elementhas an integrally formed receptacle portion which has an engagingsurface that is urged against the engaging surface of the first heattransfer element when the first heat transfer element and the secondheat transfer element are mated.

BRIEF DESCRIPTION OF THE FIGURES

[0013] The present invention is illustrated by way of example and notlimitation in the figures of the accompanying drawings.

[0014]FIG. 1 illustrates a side cross sectional view of one embodimentof a portable computing device and a docking station.

[0015]FIG. 2a illustrates a partial cross section view of one embodimentof the connection of a heat transfer element to an electronic component.

[0016]FIG. 2b illustrates a partial cross section view of anotherembodiment of the connection of a heat transfer element to an electroniccomponent.

[0017]FIG. 3 illustrates a partial elevation view of one embodiment of aheat exchanger.

[0018]FIG. 4 illustrates a cross sectional view of one embodimentincluding a spring clip compression structure which may be used with thecylindrical spring clip illustrated in FIG. 3.

[0019]FIG. 5a illustrates an elevation view of one embodiment of arectangular heat exchanger.

[0020]FIG. 5b illustrates a cross sectional view of the rectangular heatexchanger shown in FIG. 5a.

[0021]FIG. 6 illustrates a cross sectional view of the rectangular heatexchanger of FIGS. 5a and 5 b in a mated position.

DETAILED DESCRIPTION

[0022] The following description provides a thermal connector forjoining mobile electronic devices to docking stations. In the followingdescription, numerous specific details such as particular shapes, forms,and materials are set forth in order to provide a more thoroughunderstanding of certain embodiments of the present invention. It willbe appreciated, however, by one skilled in the art that the inventionmay be practiced without such specific details.

[0023] The present disclosure provides several solutions to remove heatfrom a portable computing device through a mated docking station. Someembodiments provide a durable connection which maintains a low thermalresistance despite repeated insertion and removal cycles. With theability to remove additional heat through the docking station, it may bepossible to operate components such as a processor in a portablecomputing device at a higher power level. As a result, a portablecomputing device may be able to obtain higher performance while dockedat a docking station.

[0024]FIG. 1 illustrates one embodiment of a portable computing device105 which mates with a docking station. The portable computing device105 may be a laptop computer, a notebook computer, or any other portablecomputing device which may utilize additional cooling capacity whendocked at a docking station 100. The portable computing device 105includes at least an electronic component 120 and a heat transferelement 125 to convey heat away from the electronic component.Additionally, the portable computing device includes a base 115 and adisplay 110 mounted using a hinge mechanism (not shown) at one edge ofthe base 115.

[0025] In one embodiment, the electronic component 120 is a processor;however, other components or regions of the portable computing devicemay be cooled according to the techniques disclosed herein. In a typicallaptop or notebook computer, a memory system, a disk and/or CD ROMdrive, audio and video hardware, connectivity (i.e., network and modem)hardware, as well as a power supply may all be present. These or otherindividual components as well as circuit boards or regional heat sinkswithin the portable computing device 105 may be cooled according to thepresent invention.

[0026] One end of the heat transfer element 125 is thermally coupled tothe electronic component 120. FIGS. 2a and 2 b illustrate embodiments ofthe thermal coupling of the electronic component 120 to the heattransfer element 125. In FIG. 2a, the electronic component 120 ismounted on one side of a motherboard 205 and thermally coupled to theheat transfer element 125 by several heat conducting components.

[0027] The heat conducting components of FIG. 2a include motherboardvias 210 and a heat conducting block 215. The block 215 may be analuminum block and the vias 210 may be filled with solder. The heattransfer element 125 is affixed to the heat conducting block 215 usingsolder, thermal epoxy, or other suitable means as are known or otherwiseavailable in the art. This type of mounting may be preferable if theelectronic component does not have a rigid package which can withstand adirect connection with the heat transfer element 125.

[0028]FIG. 2b illustrates an embodiment in which the heat transferelement 125 is directly mounted on an outer surface of the electroniccomponent 120 using a thermal epoxy, solder, or similar mountingmechanisms. The inner surface of the component is affixed to themotherboard 205. Either of these types of connections may be used aswell as any other means of thermally coupling the electronic component120 and the heat transfer element 125.

[0029] Referring back to FIG. 1, an end portion 135 of the heat transferelement 125 may be exposed through a closeable aperture at a mating endof the portable computing device 105 when the portable computing device105 is docked. Mechanisms known in the art or otherwise available may beused to cause a door 130 to open the closeable aperture, eitherautomatically or manually.

[0030] The docking station 100 includes a second heat transfer element145. The second heat transfer element 145 is secured to the dockingstation 100 by a pair of mounting brackets 155 a and 155 b. Other knownmounting mechanisms may be used as is convenient for a particulardocking station configuration. For instance, only a single mountingbracket may be used, or more than two mounting brackets may be used. Aset of heat dissipation fins 150 and a fan 160 as well as the heattransfer element 145 may be used as a heat dissipation mechanism in thedocking station.

[0031] A heat exchanger is formed by the mating of heat transferelements 125 and 145. One end portion 140 of the heat transfer element145 is thermally coupled to the end portion 135 of the heat transferelement 125 when the docking station 100 and the portable computingdevice 105 mate. As illustrated, in one embodiment, the heat exchangemechanism is formed by receptacle such as a spring clip 132 attached tothe heat transfer element 125 engaging a male end portion 140 of theheat transfer element 145. Alternatively, these mechanisms may bereversed so that the spring clip 132 is attached to the docking station.

[0032] In one embodiment, the heat transfer element 145 is a cylindricalor at least substantially cylindrical heat pipe. In this embodiment, thespring clip 132 is a cylindrical receptacle that engages the similarlyshaped male end portion 140. The spring clip 132 is soldered orotherwise strongly thermally and mechanically bonded to a heat pipewhich conveys heat from the electronic component 120. In otherembodiments, one or both of the heat pipes may be rectangular or anothershape as long as the spring clip 132 is also appropriately shaped tosufficiently thermally engage the end portion 140 of the heat transferelement 145 and provide a low thermal resistance path.

[0033]FIG. 3 illustrates one embodiment of the heat exchanger shown inFIG. 1. In particular, the end portion 140 of the heat transfer element145 as well as the spring clip 132 and the heat transfer element 125 areshown. In this embodiment, the end portion 140 of the heat transferelement 145 has a tapered portion 310 to facilitate insertion into thespring clip 132.

[0034] In addition, the heat transfer element has a non-plated portion325 and a plated portion 320, the plated portion 320 being plated with adurable and thermally conductive material. For example, gold,molybdenum, an alloy, or another durable and thermally conductivematerial may be used. The plated portion 320 forms an engaging surfacewhich comes into direct contact with the spring clip 132.

[0035] In the embodiment illustrated in FIG. 3, the spring clip 132 isan integrally formed separate body (i.e., it is one piece) which isaffixed to the heat transfer element 125 via a weld 340 or anothersuitable thermally conductive attachment mechanism. In some embodiments,the spring clip 132 may also be formed integrally with the entire heattransfer element 125. In either case, the resilient unitary body of thespring clip forms a receptacle with a single integrally formed body thaturges its engaging surface into contact with the heat transfer elementwhen appropriately mated. External springs or similar mechanisms may notbe necessary. The resilient unitary body of the spring clip 132 has aslit 330 allowing the spring clip 132 to deform and accommodate the heattransfer element 125.

[0036] Typically the spring clip 132 is slightly smaller than the heattransfer element 125 and expands to conform to the heat transfer element145. The spring clip 132 may also include a plated engaging surface 335and the leading edge may be beveled to further ease insertion. Similarlyto the end portion 140 of the heat transfer element 145, the engagingsurface 335 of the spring clip 132 may be coated with any appropriatethermally conductive and durable material such as gold.

[0037]FIG. 4 illustrates a spring clip compression structure 405. Thespring clip compression structure may provide additional compressionforce on a cylindrical spring clip 410, urging the spring clip 410against a heat transfer element so that a better thermal connection maybe made with the heat transfer element. The spring clip compressionstructure 405 may also allow a less resilient material to be used forthe spring clip 410. For example, without the compression structure, aspring steel material may be needed for the cylindrical spring clip 410to form an adequate contact with an inserted heat transfer element. Withthe compression structure, a less resilient material which may havebetter thermal properties (e.g., copper) may be used.

[0038] The spring clip compression structure 405 has a closed end 407and an open end 409. The closed end 407 has two elongated spring members430 and 435 which extend from the closed end and which hold the springclip 410 so that a compressing force is exerted on the spring clip 410.A weld 425 or another appropriate thermally conductive bond affixes aheat pipe 415 or other heat transfer element to the spring clip 410.Other mechanical forms which provide compressive force and/or whichsecure the heat pipe 415 and spring clip 410 may be used to provide aspring clip compression structure.

[0039]FIG. 5a illustrates one embodiment of a rectangular heat exchangeapparatus. In FIG. 5a, a rectangular heat pipe 505 with a tapered end510 having a durable plating 515 is engaged by a spring clip 522 securedin an open end of a heat pipe 520. The spring clip 522 has a housing 530which secures the spring clip 522 in the rectangular aperture formed bythe open end of the heat pipe 520. Additionally, substantially paralleland resilient plates form compressible engaging surfaces 545 and 550which respectively provide top and bottom surfaces that mate with theheat pipe 505 to provide a thermal connection. A rear surface 555 mayalso be resilient and compressible to accommodate the heat pipe 505.

[0040] As shown, the spring clip 522 has a housing 530. This housing 530may be secured in the aperture of the heat pipe 520 by forcibleinsertion. The housing 530 and therefore the spring clip 522 may bedesigned to be equal in size or marginally larger than the aperture suchthat the housing 530 remains in place once inserted. Either in additionor as a separate securing mechanism, nubs or other mechanical or bondingmeans may be used to hold the housing 530 in place.

[0041] Alternatively, the spring clip 522 itself may be formed as a partof the heat pipe 520 or as an integral part of another type of heattransfer element substituted for the heat pipe 520. The spring clip 522itself, like the cylindrical spring clip previously discussed, however,may be uncomplicated and easily manufactured integral body whichprovides an efficient durable mechanism for thermal transfer. Suchspring clip mechanisms have few moving parts and may advantageously bemanufactured and deployed in computer systems similarly to existingelectrical connectors often used between removable electroniccomponents.

[0042]FIG. 5b is a cross sectional view of the receptacle structure inFIG. 5a which illustrates several additional features which may bepresent in some embodiments. A plating 535 provides a durable highthermal conductivity interface for the heat pipe 505 like the platedsurfaces previously discussed. Additionally, the housing 530 of thespring clip 522 contains a thermally conductive and compressiblematerial 540. For example, this material may be a thermal grease, athermally conductive polymer, a thermally conductive compressibleelastomer or another thermally conductive, flexible, or yieldingmaterial.

[0043]FIG. 6 illustrates the compression which occurs to the spring clip522 shown in FIGS. 5a and 5 b when the heat pipe 505 is inserted. As canbe appreciated from FIG. 6, although the heat pipe 505 may be tallerthan the opening formed by the compressible engaging surfaces 545 and550 in their relaxed state, these surfaces compress to snugly fit theheat pipe 505 and form a strong thermal connection. The thermallyconductive and compressible material 540 maintains a low thermalresistance from the engaging surfaces 545 and 550 to the heat pipe 520despite the change in shape of the spring clip engaging surfaces.

[0044] Thus, a thermal connector for joining mobile electronic devicesto docking stations is disclosed. While certain exemplary embodimentshave been described and shown in the accompanying drawings, it is to beunderstood that such embodiments are merely illustrative of and notrestrictive on the broad invention, and that this invention not belimited to the specific constructions and arrangements shown anddescribed, since various other modifications may occur to thoseordinarily skilled in the art upon studying this disclosure.

1. A heat exchanger comprising: a first heat transfer element having afirst end which forms a first engaging surface; and a second heattransfer element having a receptacle portion, the receptacle portionbeing integrally formed and having a receptacle engaging surface urgedagainst the first engaging surface of the first heat transfer elementwhen the first heat transfer element and the second heat transferelement are mated.
 2. The heat exchanger of claim 1 wherein thereceptacle portion is a spring clip portion and the receptacle engagingsurface is a spring clip engaging surface.
 3. The heat exchanger ofclaim 2 wherein the first heat transfer element and the second heattransfer element are heat pipes.
 4. The heat exchanger of claim 2wherein the spring clip portion has a resilient unitary body which isdeformed by insertion of the first heat transfer element.
 5. The heatexchanger of claim 2 wherein the spring clip portion is fixedly mountedto provide a receptacle which is smaller than the first end of the firstheat transfer element prior to insertion into the receptacle of thefirst end of the first heat transfer element, the spring clip beingexpandable to conform to the first end of the first heat transferelement.
 6. The heat exchanger of claim 2 wherein the spring clipportion comprises a rectangular contact having resilient andsubstantially parallel plates for contacting the first heat transferelement.
 7. The heat exchanger of claim 6 wherein the second heattransfer element comprises a heat pipe having a rectangular aperturewhich houses the spring clip portion.
 8. The heat exchanger of claim 7wherein the spring clip portion further comprises a spring clip housingwhich is mounted in the rectangular aperture of the heat pipe and whichsecures the parallel plates, and further wherein a thermally conductivematerial fills a gap formed between the parallel plates and the springclip housing.
 9. The heat exchanger of claim 8 wherein the first heattransfer element is plated with a durable and thermally conductivematerial and wherein the first heat transfer element is tapered towardsthe first end.
 10. The heat exchanger of claim 9 wherein the durable andthermally conductive material is gold.
 11. The heat exchanger of claim 2wherein the spring clip portion comprises a cylindrical spring cliphaving a slit to allow expansion thereof.
 12. The heat exchanger ofclaim 11 wherein the spring clip portion is formed using spring steeland is welded to the first heat transfer element.
 13. The heat exchangerof claim 11 wherein the spring clip portion has a beveled edge whichreceives the first heat transfer element and wherein the first engagingsurface and the spring clip engaging surface are plated with a durableand thermally conductive material.
 14. The heat exchanger of claim 13wherein the durable and thermally conductive metal is gold.
 15. The heatexchanger of claim 2 further comprising: a spring clip compressionstructure attached to the spring clip portion which urges the springclip portion against the first heat transfer element when the first heattransfer element and the second heat transfer element are mated.
 16. Theheat exchanger of claim 15 wherein the spring clip portion is acylindrical spring clip which is attached to a heat pipe and wherein thespring clip compression structure has a closed end and an open end, theclosed end having two elongated spring members extending outwardly toform the open end, the spring clip portion being compressively heldbetween the two elongated spring members.
 17. A computing devicearrangement comprising: a portable computing device having an electroniccomponent therein; a docking station which receives the portablecomputing device and has a heat dissipation element therein; and a heatexchanger thermally coupling the electronic component in the portablecomputing device to the heat dissipation element in the docking station,the heat exchanger including: a first heat transfer element having afirst end which forms a first engaging surface; and a second heattransfer element having a receptacle, the receptacle being integrallyformed and having a receptacle engaging surface urged against the firstengaging surface of the first heat transfer element when the first heattransfer element and the second heat transfer element are mated.
 18. Thecomputing device arrangement of claim 17 wherein the receptaclecomprises a spring clip portion and the receptacle engaging surfacecomprises a spring clip engaging surface
 19. The computing devicearrangement of claim 18 wherein the spring clip portion comprises arectangular contact having resilient and substantially parallel platesfor contacting the first heat transfer element.
 20. The computing devicearrangement of claim 19 wherein the spring clip portion furthercomprises a spring clip housing which is mounted in a rectangularaperture of the heat pipe and which secures the parallel plates, andfurther wherein a thermally conductive and compressible material fills agap formed between the parallel plates and the spring clip housing. 21.The computing device arrangement of claim 18 wherein the spring clipportion comprises a cylindrical spring clip having a slit to allowexpansion thereof.
 22. An apparatus comprising: a mobile computingdevice having at least one electronic component therein; a deviceincluding a heat dissipation means for dissipating heat, the devicehaving a receptacle which mates with the mobile computing device; andheat transfer means for thermally coupling the at least one electroniccomponent in the mobile computing device to the heat dissipation meansin the stationary computing device, the heat transfer means comprising:a first heat transfer element coupled to the at least one electroniccomponent; a second heat transfer element coupled to the heatdissipation means; and a spring clip means for removably coupling thefirst heat transfer element to the second heat transfer element.